Steve I use the same clause which I got after a company asked me to update a search they had already done - which contained this clause.  Thought if they use it, I am too.  Mine specifically adds something to the effect of "...not responsible for mis-indexed items by the county clerk's office."  I still carry E&O insurance as I have coverage for notary services, etc. in my insurance and I do alot of larger projects such as highway expansion research.